Thought this might be helpful as a lot of these mini PCs are hitting the used market.
Then just go with the warranty. Good brands are obviously well known: Cooler Master, Corsair, TerraMaster, Orico, ASUS…etc.
TerraMaster, Orico
I honestly have never used either of these, yet they show up at a lot of retailers.
ASUS is a bit sketchy these days IMO, so I try to avoid them.